Automatic machine control device

ABSTRACT

A mechanism for disabling the operation of a change-computing cash register whenever the amount tendered by the customer is less than the amount due.

Inventors Bernhard 0. A. Kasper;

Friedrich Rombach, both oi Augsburg, Germany Appl. No. 802,072

Filed Feb. 25, 1969 Patented Sept. 7, 1971 Assignee The National CashRegister Company Dayton, Ohio Priority Apr. 26, I968 Germany P 17 74182.1

AUTOMATIC MACHINE CONTROL DEVICE [56] References Cited UNITED STATESPATENTS Re. 25,431 8/1963 Becker 235/7.l 1 3,049,288 8/l962 Becker235/7.l 1

Primary Examiner-Richard B. Wilkinson Assistant Examinen-John F.Gonzales Attorneys-Louis A. Kline, Wilbert Hawk, Jr. and Richard W.

Lavin 7 Claims, 9 Drawing Figs.

[15. Cl 235/7 A lnt.Cl G07g 1/00 ABSTRACT: A mechanism for disabling theoperation of a Field ofSearch v 235/7, 7.1, change-computing cashregister whenever the amount ten- 7.1 l, 2 dered by the customer is lessthan the amount due.

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sisoaisoa PATENTEU SEP 1 l97l SHEET 1 [IF 6 INVENTORS BERNHARD O. A.KASPER FRlEDRICH BY W mfibl QdOa ndOm N mOn ROM CH THEIR ATTORNEYSPATENTEU sz? 1 new SHEET 2 OF 6 mvEmoRs ssrmumo O.A. KASPER FalsoalpnROM THEIR ATTORNEYS aLsoalsos PATENTED SEP 7 |91| SHEET 3 BF 6 INVENTORSBERNHARD O-A. KASPER Fgglf: ROMBACH BY 4 fizz THEIR ATTORNEYSPATENTEDSEP H97! SHEET U 0F 6 FIG. 4

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INVENTORS BERNHARD O. A. KASPER FRI omen ROM ACH 5/10 a M M %2Z%h THEIRATTORNEYS PATENTEDSEP mm 35031503 SHEET 5 OF 6 NTORS O. A. KASPER THEIRATTORNEYS BERNH AUTOMATIC MACHINE CONTROL DEVICE CROSS-REFERENCES TORELATED APPLICATIONS BACKGROUND OF THE INVENTION Cash registers of thetype disclosed in US. Pat. No. 2,853,232, issued Sept. 23, 1958, on theapplication of May A. Goodbar-ct al.,contain a mechanismwhichautomatically computes thechange due to the customer after the amounttendered has been entered into the cash register. This changecomputation operation is initiated by the depression of the AmountTendered key. In the present embodiment, whenever the Amount Tenderedkey is depressed, the machine cycles to enter the amounttendered intothe totalizer, followed automatically 'by another machine operation,which computes the change due to the customer. This last operationterminates the salestransaction.

If the amounttendered is less than the amount due, the above=mentionedconstruction prevents the machine from showing, on the receipt slip,that the deficit was paid, the operator" being required to make a noteas to whether the deficit'was paid or not; A further drawback of thistype of cash register construction is that the operator is easily liableto overlook'that the amounttendered by the customer-for paying for wh'athe has'bought is' too small. Therefore it is an object of this inventionto provide an improved change-computing control devicewvhich"forces'theoperator to manually terminate the sales transaction whenever the amounttendered is less than the amount due.

SUMMARY OF TI-IEINVENTION Achange-computing mechanism includinga-control detent member'settable underthe control of an add-subtracttotal- 'izer; the'control detent member controlling the cyclic operation of the'machine.

BRIEFDESCRIPTION OF THE DRAWINGS FIG. lfis a partial detailed side viewof the transaction row -of keys of'the cash register, showingthecontrol-key-operating mechanism shown conditioned for operation by a cam'memberonthe main cam shaft.

FIG..3 is another view of the device shown in FIG. 2 in its position atabout 355- of the revolution-of the main cam shaft.

FIG. 4 as partial detailed top view of the control-keyoperatingmechanism'positioned when'the amount tendered is less than the amountdue.

FIG. 5 is a partial detailed top' view of the control-keyoperatingmechanism positioned when the amount tendered is equal to the amountdue.

FIG.-6 is a partial detailed top view of the control-keyoperatingmechanism positioned when the amount tendered is greater than the amountdue.

FIG. 7, on the sheet with FIG. 9, is a partial detailed side view of theadd-subtract'or balancetotalizer, showing the sensing mechanism'forsensing the condition of the balance totalizer and its connection to thecontrol detent.

FIG. 8 isa partial detailed front view of the add-subtract or balancetotalizer with'the balance totalizer interconnecting gears viewed at atop oblique angle while the sensing mechanism and the control platemember have been revolved and extended for purposes of clarity.

' balance totalizer.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. I, thereis shown a partial side view of the transaction or control key bank usedin the cash register of the present embodiment. As is well known in theart, depression of any of the control keys 21 initiates a machineoperation and controls the totalizer mechanism to position apredetermined totalizer element or pinion for operation. Referenceshould be made to the previously cited Goodbar et al. U.S. Pat. No.2,853,232 for a complete disclosure of the construction and operation ofthe transaction key bank and its control of the totalizer mechanism.

As shown in FIG. 1, there are control keys in Positions 3, 5, 7, 8, and9 In positions 1 and 2, there are key stems 22 but no key tips, whilekey positions 4 and 6 are combined to be operated by a single key tip(not shown). Key positions I and 2 arereferred to asblind control keys.As will be described more fully hereinafter, these blind control keysare operated automatically-Le, depressed-depending on the position of anadd-subtract totalizer mechanism.

Referring to FIG. 8, there is shown the add-subtract or balancetotalizer line utilized in the present invention. As is well known inthe art, a cash register may have any number of lines of totalizerelements or pinions. In the present embodi ment, there are two lines oftotalizer pinions. In addition to the add-subtract or balance totalizershown in FIG. 8, there is one other line of group totalizers (notshown). The balance totalizer (FIG. 8) includes a shaft 23, on which arerotatably mounted seven sets of add-subtract totalizer'pinions, therebeing one set of pinions for each amount bank of the machine. Includedin each set are a plus totalizer pinion 24 and a negative totalizerpinion 25, which are interconnected by a gear system 26, so that, whenone pinion is rotated in one direction,

the other pinion is rotated a similarextent in the opposite direction.Reference should be made to the previously cited Goodbar et al. US. Pat.No. 2,853,232 for a complete disclosure of the construction andoperation of an add-subtract totalizer.

The totalizer shaft 23 is supported by a pair of frame members 27, 28,which in turn are connected by a shaft 30 mounted therebetween. Theshaft 30 is slidably supported by a second pair of frame members 31, 32,which are supported by ashaft 33 mounted on a pair of frame members 34,35. The unitary totalizer structure, which includes both the shafts 23and 30, is shifted laterally by a mechanism (not shown) which iscontrolled by the control keys 21 (FIG. 1) to align either the pluspinion 24 or the minus pinion 25 with the actuator member (not shown) ineach amount bank. Thus, when the control keys 21 in either of positions7 and 8 (FIG. I) are depressed, the totalizer structure is shiftedlaterally to align the plus totalizer pinion 24 with the amountactuator, while the operation of the control key in key position 9 (FIG.I) aligns the minus totalizer pinion 25. The use of these keys alsoaligns their own group totalizer pinions in the second totalizer line(not shown) for the entry of amounts therein in a manner well known inthe art.

The control keys in positions 4 and 6 (FIG. I) are combined so as toforms a single combination key having a double function. In connectionwith at least one amount key of the machine, it causes amounts to beentered into the plus pinions 24 and into its own group totalizer.Depression of the combination key without anamount key makes it act as atotaltaking key or a subtotal-taking key, respectively, for the balancetotalizer.

As shown in FIG. 8 and more particularly in FIG. 7, positioned adjacentand engaging each of the plus pinions 24 in a locking relationship is acontrol plate 36, which contains a notch 37 representing the zeroposition of the plus pinion 24. Cooperating with the balance totalizeris a sensing mechanism effective to sense the condition of the balancetotalizer after the amount tendered has been entered. This sensingmechanism includes a yoke member 38 having a number of sensing fingers40, each finger positioned adjacent one of the control plates 36 in eachbank of add-subtract totalizer pinions. The yoke member 38 is rotatablymounted on the shaft 30 and is urged counterclockwise by a spring 41,which engages a stud 42 mounted on the yoke 38. This action results inthe sensing fingers 40 engaging the control plates 36 to sense for thenotch 37. Also associated with the control plate 36, in a manner to bedescribed hereinafter, is an overdraft control member 43 (FIG. 9), whichis positioned in either of two positions, depending on whether thebalance totalizer is in either a plus condition or a minus condition.Reference should be made to the previously cited Goodbar et al. U.S.Pat. No. 2,853,232 and to U.S. Pat. No. 2,974,860, which issued on Mar.14, 1961, on the application of Frank R. Werner et al., for a completedisclosure of the structure and operation of an overdraft mechanismassociated with an add-subtract or balance totalizer.

Referring again to FIG. 7, there is shown a U-shaped control plate 44,which is rotatably mounted on a shaft 45 and which is normally urgedclockwise by a spring 46. A lower extension 47 is positioned adjacent astud 48 mounted on the yoke member 38 and is urged into engagement withthe stud 48 by the action of the spring 46. The other end of the controlplate 44 comprises a shoulder portion 50, which is positioned adjacent abent-over tab portion 51 of a selecting detent 52. As shown in FIG. 9,the tab portion 51 is also mounted adjacent a shoulder portion 53 of theoverdraft control member 43.

As shown in FIGS. 7 and 8, the lower end of the yoke 38 has mountedthereon a stud 54, which is yoked by one end of a yoke member 55, whichin turn is rotatably mounted on a shaft 56. The other end of the yokemember 55 is engaged by a link member 57, which in turn is connected toa cam follower member 58, which is rotatably mounted on a shaft 60.Rotatably mounted on the cam follower member 58 is a cam roll 61, whichengages the edge of a cam member 62 secured to the main camshaft 63. Inthe operation of the cash register with the above-disclosedconstruction, the amount due, which is determined as a result of anumber of cash register operations in a manner well known in the art, isentered into the plus pinions 24 of the balance totalizer. The amounttendered by the customer is then entered into the keys of the amountbanks. The Amount Tendered transaction key 21 (Position 3, FIG. 1) isthen depressed to initiate a machine operation in a manner that will bedescribed more fully hereinafter. During this machine operation, theamount set up in the amount banks is entered into the minus pinions 25of the balance totalizer. If the amount tendered is greater than theamount due, the balance totalizer will be in a negative condition as aresult of the amount entry operation. If the amount tendered is lessthan the amount due, the balance totalizer will be in a positivecondition. Both of these conditions affect the position of the overdraftcontrol member 43 (FIG. 9). If the balance totalizer is in a positivecondition, the overdraft control member 43 will be in the position shownin FIG. 9, with the shoulder portion 53 blocking the movement of the tabportion 51 of the detent 52. As will be described more fullyhereinafter, the detent 52 is moved to the right, as viewed in FIG. 8,to sense the condition of the balance totalizer.

If the balance totalizer is in a negative condition, the control member43 will be rotated counterclockwise from the position shown in FIG. 9,thereby removing the shoulder portion 53 from the path of the tabportion 51 of the detent 52. This allows the detent 52 to move to theright a further distance until it is stopped by the main portion of themember 43. As shown in FIG. 9, associated with the control member 43 isan aligner member 64, which locks the member 43 in place by inserting astud in either of two slots 65, 66.

During the machine operation initiated by the depression of the AmountTendered key, the main camshaft 63 is rotated clockwise, as viewed inFIG. '7. This movement rocks the cam follower 58 first counterclockwiseabout the shaft 60 and then clockwise. During the counterclockwisemovement, the cam follower 58 will, through the link 57, rotate the yoke55 counterclockwise, which, by its engagement with the stud 54, rocksthe yoke 38 clockwise about the shaft 30, thereby withdrawing thesensing fingers 40 from engagement with the control plates 36 on thebalance totalizer. This movement also rocks the plate 44counterclockwise about the stud 45, thereby removing the shoulder 50from the path of the detent 52. After the balance totalizer has beenadjusted as a result of the machine operation, the clockwise movement ofthe cam follower 58 results in the yoke 38 being released to the actionof the spring 41, which moves the sensing fingers 40 in a direction tosense the control plates 36. If the amount tendered was equal to theamount due, the balance totalizer is positioned to align the notches 37in each of the control plates 36 so as to be sensed .by the sensingfingers 40. This movement of the sensing fingers 40 into the notches 37allows the shoulder 50 of the control plate 44 to be positioned by theaction of the spring 46 to block the movement of the detent 52, as shownin FIG. 7. If the balance totalizer was in a positive condition or anegative condition as disclosed previously, the notches 37 of thecontrol plates 36 would not be aligned with the sensing fingers 40, andthe shoulder 50 would be positioned below the tab portion SI. This wouldallow the detent 52 to move to the right, as viewed in FIG. 7, to sensethe overdraft control member 43 in the manner described previously.

As shown in FIG. 7, the selecting detent 52 is pivotally connected to akey detent member 67 by means ofa stud 68. This assembly is slidablysupported by a pair of studs 70 positioned within slots 71. The keydetent member 67 is normally urged in a sensing direction by a spring(not shown). It will thus be seen, from the mechanism just disclosed,that the detent extension 67 is positioned in one of three positions,depending on the condition of the balance totalizer after an amounttendered operation has occurred. As shown in FIG. 7, with respect to theposition of the stud 68, Position 1 will correspond to the operationwhere the balance totalizer is in a zero condition; that is, when theamount tendered is equal to the amount due. Position 2 is when thebalance totalizer is in a positive condition or the amount tendered isless than the amount due, and Position 3 is when the balance totalizeris in a negative condition or the amount tendered is greater than theamount due. In this last condition, change is due to the customer.Normally the cash register is connected to an automatic changedispenser, and, when this last condition occurs, the cash register isautomatically cycled for another operation, during which the change isdetermined and the dispenser is operated to dispense the proper changeto the customer. For a complete disclosure of this type of operation,reference should be made to U.S. Pat. No. 2,972,442, issued Feb. 2I,I961, on the application of Mayo A. Goodbar et al., which discloses theautomatic control of a change dispenser by a cash register.

As shown in FIG. 1, the key detent 67 extends along the transaction bankof keys 21. The detent 67 has an upwardly extending arm 72, which ispositioned between the first and second key positions of the transactionbank. Slidably mounted on the arm 72 is a control detent 73 (FIGS. 1, 4,S, and 6), which has a stem member 74 slidably supported in two roundrecesses in the laterally offset head 75 of an actuation rod 76.

Depression of the Amount Tendered key 21 (Position 3, FIG. 1) results ina cam disc 77 (FIGS. 2 and 3) being rotated, at about 51 of revolutionof the main camshaft, to rock an intermediate lever 78 clockwise about abolt 80, to which the lever is mounted. The cam disc 77 engages a stud81 mounted on one end of the lever 78. The position to which the leveris moved is shown in FIG. 2. The bolt 80, to which the lever 78 ismounted, is positioned within an open-ended slot 82 of the actuation rod76 and is urged by a spring 83 to a position within said slot. The otherend of the spring 83 is connected to a bolt 84 mounted on the machineframework. 1

The lever 78 is normally urged counterclockwise by a spring 85 securedto the machine framework. The other end of the lever 78 has a stud 86,which, upon the clockwise movement of the lever 78, engages a multiarmstop lever 87, rocking the lever counterclockwise about a stud 88, onwhich the lever 87 is rotatably mounted. This movement is against theaction of a spring 90 mounted on the stud 88 and engaging a stationary'stud '89. This clockwise movement of the stop lever 87 positions an armportion 91 in the path of a stud 92 mounted on a cam member 93 securedto the main camshaft 63.

At about 317 of the revolution ofthe main camshaft 63, the stud 92.engages the stop lever 87 and rocks it still farther counterclockwise,as shown in FIG. 3. This movement tensionsaspring=94mounted between astud 95 mounted on the stop-lever 87' and a' stud 96 mounted on theactuation rod 76.

Theactuation-rod 76 is normally held in its home, or upper,

position (FIGS. 1 and 2) by a locking lever 97, which is rotatablymounted on'the bolt'80, which rotatably supports which ispositioned thebolt 84, together with the bolt 80 mounted withing the open-ended slot82 of the actuation rod 76, slidably supports the actuation rod formovement. A

spring 102, secured between a'protrusion 103 and a stud 104 "mounted on'the locking lever 97, and guided over the bolt 84, .resil'ientlyconnects the actuation rod 76 and the locking lever '97 together. Withthis construction, thecounterclockwise movement given to the stop lever87 by the stud 92 results in an arm portion 105 of the lever engaging astud 106 mounted on'the locking lever" 97, thereby rocking the leverclockwise,

which movement removes the'shoulder 98 from'under the stud 100 of theactuation rod 76. This releases the actuation 'rod'76 to the action ofthe spring 94, which'pulls the actuation rod downwardly until the-bolt80 reaches the top of the slot 82 and the bolt 84 reaches the top of theslot 101. Thus it is seen that,each-time'th'e Amount Tendered key isdepressed, the actuation rod 76 moves downwardly duringthe operation ofthe machine.

The sensinggof' the add-subtract or balance totalizer results in themovement of the key detent 67 toone of three positions,'.as describedpreviously. Since the arm 72 of the detent 67* is positioned within thecontrol detent 73, the shifting of the-detent 67 also results in theshifting of the control detent 73:and its associated stern member 74'.Thus, when the detent member-67 is moved to Position 1 (FIG. 7) due tothe balance 'totalizers being in a zero condition, the control detent 73is :shiftedso that the stem member 74 is positioned above the stem 22 ofPosition 1(FIG. 5) blind key. Upon the operation 'of thecontrol detent73 in the manner described above, as a' result of theactuation of theAmount Tendered key, a further machine operation is automaticallyinitiated by the depression of the key stem22 by the stem 74 of thecontrol detent 73. During the latter operation, the change dispenser isoperated but does not give any change, while 0.00 change" is indicatedand is printed on a receipt, which receipt is fed out from the machineto a position to be separated from the supply roll by the operator.

When the detent 67 is moved to Position 2 (FIG. 7) due to the balancetotalizers being in a positive condition, the control detent 73 isshifted to a position between the key stems 22 (FIG. 4) of the blindkeys in Positions 1 and 2. Upon the downward movement of the controldetent 73, neither blind key is actuated. As a result, no furthermachine operation is initiated at the end of the machine operationinitiated by the actuation of the Amount Tendered key. This stopping ofthe machinebrings to the operator's attention the fact that the amounttendered is too small and the sales transaction, therefore, has not cometo an end yet.

Such a change-computing operation may then be completely terminated bythe use ofa Balance Due control key located in Position 5 (FIG. 1) ofthe transaction key bank. The amount equal to the balance due would thenbe indicated and would be printed on the receipt that is issued.

When the detent 67 is moved to Position 3 (FIG. 2), due to the balanceor add-subtract totalizers being in a negative condition, the controldetent 73 and its stern member 74 are shifted to a position (FIG. 6)over the blind key in Position 2, which results in a subsequent machineoperation similar to the operation of the blind key in Position 1, asdescribed previously. During this latter operation, the change dispenseris operated to dispense change.

At approximately 36 of the revolution of the main camshaft 63 duringthelast machine operation, the stop lever 87 (FIGS. 2 and 3) is releasedfrom the stud 92 mounted on the cam member 93, therebyallowing thecontrol detent actuating mechanism to be restored to its home positionunder the actionof the springs 85, 90, and 102 (FIGS. 2 and 3).

It is thus seen from this construction that the operator is preventedfrom completing the sales transaction whenever the amount tenderedisless than the amount due, which then requires that the sales transactionbe manually completed by some'other action.

What is claimed is:

1. In a machine capable of indicating, registering, and recording theamounts due and the amount tendered in a sales transaction and includingan add-subtract totalizer-for computing the change from the amounttendered and the amount due entered into the totalizer and a pluralityof control keys for releasing the machine for operation when actuated,the combination including a. an actuating member slidably mountedadjacent a control key, for movement between a first position and asecond position, said actuating member being conditioned, when operated,to actuate said control key when in said second position and to disablesaid control key from actuation when in said first position;

b. control means operated during each machine operation;

0. means interconnecting said actuating member and said control means; i

d. means for moving said actuating member between said first and secondpositions including a first control member positioned by saidadd-subtract totalizer and having a first control surface, said firstcontrol surfacebeing moved to a predetermined position by theadd-subtract totalizer when the amount tendered is less than the amountdue;

e. first sensing means mounted adjacent said first control memberandengaging said actuating member for sensing said first controlsurface;

f. and means for moving said sensing means in a sensing directionwhereby, upon sensing said first control surface in said predeterminedposition, said first sensing means moves said actuating member to saidfirst position, thereby disabling any further operation of the machine.

2. The machine of claim 1 which includes a second control member securedto said add-subtract totalizer and having a second control surface, saidsecond control surface being moved to a predetermined position by theadd-subtract totalizer when the amount tendered is equal to the amountdue;

second sensing means mounted adjacent said second control member andsaid first sensing means for sensing said second control surface, theposition of the second sensing means being sensed by said first sensingmeans;

and means for moving said second sensing means in a direction to sensesaid second control surface whereby, upon sensing said second controlsurface in said predetermined position, said second sensing means ispositioned to allow said first sensing means, in sensing the position ofsaid second sensing means, to move said actuating member to said secondposition.

3. The machine of claim 2 in which the add-subtract totalizer includes aplus and minus totalizer pinion, the amounts due being en tered intotheplus totalizer pinion and the amount tendered being entered into theminus totalizer pinions;

said second control member being secured to the plus totalizer pinion;

and said second control surface comprises a notch in said second controlmember whereby, upon the sensing of the notch in the predeterminedposition by said second sensing means, the first sensing means will movesaid actuating member to said second position to initiate a furthermachine operation.

The machine of claim 1, in which said control keys include an amounttendered key operated during the entering of the amount tendered intothe add-subtract totalizer;

said control means includes a cam member operated during each machineoperation;

said interconnecting means includes motion-transmitting means mountedadjacent said cam member and engaging said actuating member;

and drive means mounted adjacent said motion-transmitting means andactuated by the operation of said amount tendered key to move saidmotion-transmitting means into engagement with said cam member wherebythe cam member will operate said actuating member during a machineoperation.

In a machine capable of indicating and registering the amounts due andthe amount tendered in a sales transaction and including an add-subtracttotalizer for computing the change from the amount tendered and theamount due entered into the totalizer and a plurality of control keysfor releasing the machine for operation when actuated, the combinationincluding an actuating member slidably mounted between two of saidcontrol keys for movement to a position adjacent either of said controlkeys and to a position between said control keys;

control means operated during each machine operation;

. means interconnecting said actuating member and said control means toallow said control means to operate said actuating member whereby saidactuating member will actuate either of said control keys whenpositioned adjacent thereto, thereby releasing the machine foroperation;

. means for moving said actuating member adjacent either of said controlkeys or between said keys including a first control member positioned bysaid add-subtract totalizer after the amount tendered has been enteredinto said totalizer; said first control member having a first controlsurface and a second control surface, said first control surface beingmoved to a first predetermined position when the amount tendered is lessthan the amount due, while said second control surface is moved to saidfirst predetermined position when the amount tendered is greater thanthe amount due;

. a second control member secured to said add-subtract second sensingmeans mounted adjacent said first control member and first sensing meansand engaging said actuating member for sensing either of said first,second, or fourth control surfaces in said first predeterminedposition',

. and means for moving said first and second sensing means in a sensingdirection whereby said actuating member is positioned adjacent saidcontrol key to initiate a further machine operation upon the sensing bysaid second sensing means of either the second or the fourth controlsurface and is positioned between said control keys to disable a furthermachine operation upon the sensing of said first control surface.

6. The machine of claim 5, in which said first, second, and fourthcontrol surfaces comprise stop surfaces; and said third control surfacecomprises a notch in said second control member whereby, upon sensing ofsaid notch by said first sensing means, said fourth control surface ispositioned to stop the movement of said second sensing means, therebypositioning said actuating member adjacent one of said control keys.

7. The machine of claim 5 in which the control keys mounted adjacentsaid actuating member comprise blind key stems, said second sensingmeans slidably supports said actuating member for vertical movement,

and said control means includes a cam member to move said actuatingmember in a downward direction to actuate said blind key stems when saidactuating member is positioned adjacent said blind key stems.

1. In a machine capable of indicating, registering, and recording theamounts due and the amount tendered in a sales transaction and includingan add-subtract totalizer for computing the change from the amounttendered and the amount due entered into the totalizer and a pluralityof control keys for releasing the machine for operation when actuated,the combination including a. an actuating member slidably mountedadjacent a control key, for movement between a first position and asecond position, said actuating member being conditioned, when operated,to actuate said control key when in said second position and to disablesaid control key from actuation when in said first position; b. controlmeans operated during each machine operation; c. means interconnectingsaid actuating member and said control means; d. means for moving saidactuating member between said first and second positions including afirst control member positioned by said add-subtract totalizer andhaving a first control surface, said first control surface being movedto a predetermined position by the add-subtract totalizeR when theamount tendered is less than the amount due; e. first sensing meansmounted adjacent said first control member and engaging said actuatingmember for sensing said first control surface; f. and means for movingsaid sensing means in a sensing direction whereby, upon sensing saidfirst control surface in said predetermined position, said first sensingmeans moves said actuating member to said first position, therebydisabling any further operation of the machine.
 2. The machine of claim1 which includes a second control member secured to said add-subtracttotalizer and having a second control surface, said second controlsurface being moved to a predetermined position by the add-subtracttotalizer when the amount tendered is equal to the amount due; secondsensing means mounted adjacent said second control member and said firstsensing means for sensing said second control surface, the position ofthe second sensing means being sensed by said first sensing means; andmeans for moving said second sensing means in a direction to sense saidsecond control surface whereby, upon sensing said second control surfacein said predetermined position, said second sensing means is positionedto allow said first sensing means, in sensing the position of saidsecond sensing means, to move said actuating member to said secondposition.
 3. The machine of claim 2 in which the add-subtract totalizerincludes a plus and minus totalizer pinion, the amounts due beingentered into the plus totalizer pinion and the amount tendered beingentered into the minus totalizer pinions; said second control memberbeing secured to the plus totalizer pinion; and said second controlsurface comprises a notch in said second control member whereby, uponthe sensing of the notch in the predetermined position by said secondsensing means, the first sensing means will move said actuating memberto said second position to initiate a further machine operation.
 4. Themachine of claim 1, in which said control keys include an amounttendered key operated during the entering of the amount tendered intothe add-subtract totalizer; said control means includes a cam memberoperated during each machine operation; said interconnecting meansincludes motion-transmitting means mounted adjacent said cam member andengaging said actuating member; and drive means mounted adjacent saidmotion-transmitting means and actuated by the operation of said amounttendered key to move said motion-transmitting means into engagement withsaid cam member whereby the cam member will operate said actuatingmember during a machine operation.
 5. In a machine capable of indicatingand registering the amounts due and the amount tendered in a salestransaction and including an add-subtract totalizer for computing thechange from the amount tendered and the amount due entered into thetotalizer and a plurality of control keys for releasing the machine foroperation when actuated, the combination including a. an actuatingmember slidably mounted between two of said control keys for movement toa position adjacent either of said control keys and to a positionbetween said control keys; b. control means operated during each machineoperation; c. means interconnecting said actuating member and saidcontrol means to allow said control means to operate said actuatingmember whereby said actuating member will actuate either of said controlkeys when positioned adjacent thereto, thereby releasing the machine foroperation; d. means for moving said actuating member adjacent either ofsaid control keys or between said keys including a first control memberpositioned by said add-subtract totalizer after the amount tendered hasbeen entered into said totalizer; said first control member having afirst control surface and a second control surface, said first controlsurface being moved to a first predetermined position when the amounttendered is less than the Amount due, while said second control surfaceis moved to said first predetermined position when the amount tenderedis greater than the amount due; e. a second control member secured tosaid add-subtract totalizer and having a third control surface, saidthird control surface being moved to a second predetermined position bysaid totalizer when the amount tendered is equal to the amount due; f.first sensing means mounted adjacent said second control member andhaving a fourth control surface, said sensing means being adapted tosense said third control surface, thereby positioning said fourthcontrol surface in said first predetermined position when said thirdcontrol surface is sensed in said second predetermined position; g.second sensing means mounted adjacent said first control member andfirst sensing means and engaging said actuating member for sensingeither of said first, second, or fourth control surfaces in said firstpredetermined position; h. and means for moving said first and secondsensing means in a sensing direction whereby said actuating member ispositioned adjacent said control key to initiate a further machineoperation upon the sensing by said second sensing means of either thesecond or the fourth control surface and is positioned between saidcontrol keys to disable a further machine operation upon the sensing ofsaid first control surface.
 6. The machine of claim 5, in which saidfirst, second, and fourth control surfaces comprise stop surfaces; andsaid third control surface comprises a notch in said second controlmember whereby, upon sensing of said notch by said first sensing means,said fourth control surface is positioned to stop the movement of saidsecond sensing means, thereby positioning said actuating member adjacentone of said control keys.
 7. The machine of claim 5 in which the controlkeys mounted adjacent said actuating member comprise blind key stems,said second sensing means slidably supports said actuating member forvertical movement, and said control means includes a cam member to movesaid actuating member in a downward direction to actuate said blind keystems when said actuating member is positioned adjacent said blind keystems.